Descent of Man [ 1871]

Chapter II - On the Manner of Development of Man from some Lower Form

  IT is manifest that man is now subject to much variability. No two
individuals of the same race are quite alike. We may compare
millions of faces, and each will be distinct. There is an equally
great amount of diversity in the proportions and dimensions of the
various parts of the body; the length of the legs being one of the
most variable points.* Although in some quarters of the world an
elongated skull, and in other quarters a short skull prevails, yet
there is great diversity of shape even within the limits of the same
race, as with the aborigines of America and South Australia- the
latter a race "probably as pure and homogeneous in blood, customs, and
language as any in existence"- and even with the inhabitants of so
confined an area as the Sandwich Islands.*(2) An eminent dentist
assures me that there is nearly as much diversity in the teeth as in
the features. The chief arteries so frequently run in abnormal
courses, that is has been found useful for surgical purposes to
calculate from 1040 corpses how often each course prevails.*(3) The
muscles are eminently variable: thus those of the foot were found by
Prof. Turner*(4) not to be strictly alike in any two out of fifty
bodies; and in some the deviations were considerable. He adds, that
the power of performing the appropriate movements must have been
modified in accordance with the several deviations. Mr. J. Wood has
recorded*(5) the occurrence of 295 muscular variations in thirty-six
subjects, and in another set of the same number no less than 558
variations, those occurring on both sides of the body being only
reckoned as one. In the last set, not one body out of the thirty-six
was "found totally wanting in departures from the standard
descriptions of the muscular system given in anatomical text books." A
single body presented the extraordinary number of twenty-five distinct
abnormalities. The same muscle sometimes varies in many ways: thus
Prof. Macalister describes*(6) no less than twenty distinct variations
in the palmaris accessorius.

  * Investigations in the Military and Anthropological Statistics of
American Soldiers, by B. A. Gould, 1869, p. 256.
  *(2) With respect to the " Cranial forms of the American
aborigines," see Dr. Aitken Meigs in Proc. Acad. Nat. Sci.
Philadelphia, May, 1868. On the Australians, see Huxley, in Lyell's
Antiquity of Man, 1863, p. 87. On the Sandwich Islanders, Prof. J.
Wyman, Observations on Crania, Boston, 1868, p. 18.
  *(3) Anatomy of the Arteries, by R. Quain. Preface, vol. i., 1844.
  *(4) Transactions of the Royal Society of Edinburgh, vol. xxiv., pp.
175, 189.
  *(5) Proceedings Royal Society, 1867, p. 544; also 1868, pp. 483,
524. There is a previous paper, 1866, p. 229.
  *(6) Proc. R. Irish Academy, vol. x., 1868, p. 141.